The use of electronic scanner-reader devices equipped with optical sensing heads to pick-up and transmit from either manual or mechanical presentation of a bar coded target pattern product identification, pricing, or inventory data in facilitating automated product handling, processing, or control procedures is now well developed and established and in widespread daily use. Successful and reliable utilization of the foregoing technology, however, depends upon a number of factors, among which are first the requirements for high standards of printed bar code image quality in order to enable and enhance accurate optical sensing and consistent reading, and second in order to enhance the accuracy of bar code scanning the bar code image target pattern must be of a sufficient size to be picked up with reasonable facility in either a manual or mechanical pass thereof for scan and sensing.
With regard to the requirement for high standards of printed bar code image quality, the bar code images must be of uniform thickness with straight sharp edges and uniform parallel spacing between them so that a target pattern of high resolution is presented to the optical sensing head. With regard to the second requirement, the larger the target pattern the more easily it is acquired and read by either manual or mechanical presentation to an optical scanning device sensing head for reading.
For purposes of providing a high standard of printed bar code image quality on such an item, in say label printing, with a reasonable degree of flexibility in printing options and product output at reasonable printing speeds, the computer driven and controlled class of pulsing hammer printers employing printing drums, thimbles, daisy wheels or the like with raise-engraved fixed font characters represents that which is probably the currently available optimum of printing equipment for producing items such as labels with bar code character target patterns in combination with human readable matter.
However, until the present invention, raise-engraved fixed font bar code characters, and thus the printed image generated therefrom upon a label or the like by and on the computer driven and controlled pulsing hammer class of printers, have been limited in height as a consequence of the hammer size or mass that could be cycled with the speed and accuracy otherwise possible. It is a simple mechanical fact that as hammer size and mass is increased, in order to accommodate the printing of larger character sizes in the font, there is a rapid degredation of the printed character image quality.
Bar code characters are essentially vertical line images printed in a spaced parallel disposition whereby the machine readable information coding imbedded therein is a function of the pattern of an array of varying width combinations of such lines. Therefore, to print an extended height bar code pattern, if one cannot mechanically accomplish that end at retained accuracy and speed by simply increasing both pulsing hammer size and mass in combination with a corresponding increase in bar code font character size, then other approaches are necessary. Another application which is electro-mechanically similar, but functionally distinguished, is the teaching by Mia et al in U.S. Pat. No. 4,320,980 dated Mar. 23, 1982, for reverse printing light characters on a dark background.
The instant invention, however, discloses a method for employing standard computer driven pulsing hammer raise-engraved fixed font printers of that type wherein the long axis of the bar code font characters are disposed parallel to the lateral edge direction of pitch advance feed of the print stock material for printing extended height continuous vertical lines in the form of bar code characters with standard size pulsing hammers but employing a font of bar code raise-engraved characters which are of a slightly greater elevation than the pitch advance of the printing stock thereby enabling the generation of larger printed bar code pattern target images being to any height multiple of pitch advances desired, by a simple technique of bar code printed image aligned and abutted overlap printing, accomplished in concurrently printed combination with human readable matter, all on a single printer pass without the need for reverses and repetitive incremental feeds of printing stock less than that of the normal sequential pitch advance of the particular machine being employed.